This is a revised competing continuation application in which three years of funding are requested to support studies designed to increase our knowledge base regarding the transmission of sounds and vibrations into the uterus and their effects on the fetus. The applications contains two basic sets of studies. One set is directed toward the evaluation of sound and contains three specific aims. First the applicant wishes to assess the levels of external sound which can mask fetal auditory evoked potentials. Second, the applicant wishes to evaluate the changes in auditory evoked potentials resulting from exposure of the fetus to airborne sound at approximately 0.8 gestation. The actual evaluation of the effects will be done following birth. Third, the applicant proposes to evaluate the intelligibility of speech sounds recorded from the inner ear of the fetus. The other set of studies is directed toward vibration and also contains three specific aims. The applicant wishes to describe the effects of sign wave vibration of the abdomen of the pregnant ewe on accelerations levels of the maternal abdominal wall and fetal head. He also wishes to determine the role of the vestibular system in the fetal response to vibration of the maternal abdominal segment. Finally, he wishes to describe the effects of impact vibration of the maternal abdominal wall on vibratory responses of the fetal head. The animal models chosen for study are the pregnant ewe, its fetus and the newborn lamb.